Convertible sofas or sofa bed recliners are well known. Many of these sofas require substantial effort to open the sofa, to convert the sofa to a bed or close the bed to form a sofa. For many of the currently available sofa bed recliners it is also required that the sofa bed recliner be a substantial distance from a wall when it is opened or closed. In addition, the frames currently available frequently require intricate mechanisms to maintain the bed in a rigid position when the sofa is open into a bed and to maintain the sofa back and seat firmly in position when the sofa is in the closed position.
The problem associated with opening a sofa when in close proximity to a wall has been addressed by U.S. Pat. No. 4,875,244. However, the frame described therein does not provide means for rigidly maintaining the bed flat when the sofa is in the open position. Furthermore, the mechanism for opening and closing the sofa relies on a gravity activated cam and the mechanism can be subject to sticking.
The problem of maintaining a sofa in a rigid position when in the open position has been overcome in part by U.S. Pat. No. 4,642,823 which employs locking pins slidably mounted in the seat member of the sofa which slidably engage holes in the back member of the sofa when the sofa is opened to form a bed. The shortcoming of this mechanism is that alignment of the pins with the holes is critical.
Thus there is a need of a simple hinge mechanism that will provide for positive activated opening and closing of the sofa and will operate when the sofa is positioned near a wall.